The RCMI program at the Universidad Central del Caribe aims to develop the research infrastructure of this institution by strengthening research administrative structure, modernizing the biomedical technology, providing start-up support to specific research projects and increasing external and internal scientific interaction. This effort is envisioned as the key to develop productive and competitive research. The present program is composed of two units: research support services meeting common needs and a research activity unit with clusters of researchers sharing similar interests and methodologies. Currently, two of these clusters form the non-AIDS component and an additional one the Retrovirus Research Center. Consistent with the UCC-RCMI research goals, the centers, within the research activity unit, are actively engaged in procuring research support to foster individual research activities by its members and to increase the critical mass of qualified researchers in the study of diseases that affect our community. The RCMI-supported Cardiovascular Research Center (CRC), a non-AIDS activity, aims at providing an adequate environment to stimulate basic and clinical research on cardiovascular medicine in order to develop new strategies for clinical management. Two pilot projects submitted in this second RCMI supplemental grant application will be integrated as part of the ongoing expansion plan of this Center: the Possible Protective Effects of Calpain Inhibitors Against Hypoxic Myocardial Cell attempts to determine whether there is correlation between hypoxic cell injury and intracellular calpain activity in cultured myocytes under hypoxia; the second project seeks to identify some of the molecular components involved in the activation/deactivation and/or regulation of the pH and volume sensitive Na+/H+ exchangers in Amphium red blood cells. The RCMI-supported Retrovirus Research Center (CRC) deals with all AIDS-related research activities for a more efficient and effective use of resources to study retroviruses. It comprises the HIV-registry and Immunoretrovirology Laboratory integrated into an ongoing, coordinated, comprehensive care plan for HIV-infected patients. Funds for one project associated with this Center is requested int he present supplemental application: Correlates of HIV Risk Behavior Among Adolescent Students in Puerto Rico. This study proposes to develop a model which could explain Puerto Rican adolescent's risk behaviors.